Static electricity causes problems ranging from a mere nuisance to degradation and catastrophic failures of electrical devices when tribo-electric charges build up on a person and are then discharged into electronic equipment upon contact. The advent of large scale integration of electrical components has resulted in even greater sensitivity to electro-static discharge ("ESD"). One estimate of the cost of ESD-caused information loss, disruption, and damaged equipment is as high as $10 billion per year. Consequently, many methods have been employed to combat ESD in manufacturing and other facilities where sensitive electronic components are exposed.
With regard to ESD controlled surfaces such as floors, it has become apparent that a major component of the total electrical continuity sought to be achieved in preventing ESD is the adhesive used to secure the ESD floor covering. This is because in most work environments, the floor is one of the largest single surfaces and the primary source of static-charge buildup. To combat this problem, conductive or static dissipative flooring is often applied, usually in the form of tiles, modules, or roll goods. The adhesive or cement used to secure the tiles to the existing flooring must itself provide for and facilitate continuous electrical continuity from tile to tile, and from tile to ground. Therefore, various conductive adhesives have been developed. The most generally used type is a conductive epoxy. Epoxies, by their nature, however, are nonreleasable and therefore not desirable for modular floors which otherwise allow for easy reconfiguration. Additionally, epoxy does not facilitate easy replacement of individual tiles which have become worn or damaged. There are other reasons epoxies are not desirable for many applications. Some epoxies require a long set-up time which disrupts operations and increases the overall cost associated with installing the ESD flooring. Because of its consistency, conductive epoxy is difficult to apply, further adding to the cost of installation. Additionally, epoxies involve a mixing of resin and hardener before application, and often require special handling and ventilation because of the strong odors generated by the epoxies. Generally, epoxies also have a very short mixed or pot life. Finally, epoxies are often difficult to correctly apply to achieve the desired conductivity and also difficult to clean off tools, furniture, and equipment. Most importantly, however, epoxy applied to ESD flooring does not allow the flooring to be easily reconfigured or releasable and does not allow easy replacement of worn or damaged individual tiles.
Modular ESD flooring in the form of tiles is desirable for many applications since a given area can be easily reconfigured and maintained. Furthermore, this type of ESD flooring allows easy access to wiring running in the floor. Releasable adhesives allow such reconfiguration and maintenance, but there is currently no effective releasable conductive adhesive for ESD flooring. Using releasable type adhesives, some attempts were made to develop a conductive adhesive for ESD flooring. For example, carbon black powders have been added to currently available releasable adhesives. The result, however, was that the carbon diluted the tackiness and strength of the dry adhesive rendering it unusable.